The present invention relates to vehicle suspension systems, and more particularly, to a cross-bar hydraulic suspension system for preventing the roll of an automobile during turning.
When a vehicle is steered through a turn by a driver the vehicle is subjected to centrifugal forces tending to roll the vehicle body radially outwardly of a circular path of travel of the vehicle. Modern passenger cars often have soft suspension springs for a more comfortable ride. However in such cars the roll can develope into a large angle due to the roll moment produced during the turning of the vehicle, and excessive lateral inclination of the vehicle is experienced. As a result, the driver and passengers are subjected to more discomfort during the turn, and maneuverability and driving safety is also reduced.
Various anti-roll systems have been proposed for preventing a vehicle from rolling during a turn. However they either do not effectively limit the roll without sacrificing a smooth ride, or they are unduly complex and expensive.
U.S. Pat. No. 4,354,567 of Puchas and assigned to Daimler-Benz, AG, discloses a rear axle assembly including triangular tilted control arms which are employed to suspend the driven wheels from the body. When increased lateral forces act on the wheels during a turn, the effect produced is so-called "lateral force understeer."
U.S. Pat. No. 4,345,661 of Nishikawa and assigned to Honda, discloses an anti-roll system for a vehicle equipped with power steering for producing a steering reactive force modulated by the speed at which the vehicle is running. The system introduces pressurized hydraulic fluid for the steering reactive force into four individual shock absorber type assemblies connected with each wheel in a McPherson strut arrangement.
U.S. Pat. No. 4,281,850 of Studer discloses an anti-sway apparatus comprising a transverse beam elastically connected at each end with a transverse axle supported by leaf springs. The beam is in turn pivotally connected at each end to the vehicle body.
U.S. Pat. No. 4,277,076 of Hanna discloses a hydropneumatic anti-roll suspension system including a hydraulic actuator for suspending each wheel from the vehicle body and a spring accumulator.
U.S. Pat. No. 4,076,275 of Hiruma discloses a hydropneumatic vehicle suspension system for body height control including four hydraulic piston/cylinder assemblies.
U.S. Pat. No. 4,054,303 of deKruyff and assigned to General Motors discloses a stabilizer bar arrangement for the front end of a vehicle. It includes cross-bars secured at their outer ends to the oppositely disposed lower control arms and having juxtapositioned inner ends, with a slot formed in one cross-bar and a pin mounted in the other cross-bar and extending into the slot.
U.S. Pat. No. 4,030,777 of Rabenseifner and assigned to Volkswagenwerk, AG, discloses a suspension system having separate hydraulic cylinders for each wheel. The movement of the piston in each cylinder in response to different loadings of the associated wheel of the vehicle controls the flow of pressurized fluid to and from the device so as to maintain the piston within a predetermined range of positions relative to the cylinder.
U.S. Pat. No. 3,893,680 of Marcillat et al. discloses a device for limiting transverse leaning of a vehicle which utilizes pendulum type electric switches for controlling the flow of hydraulic fluid into and out of multiple cylinders.
U.S. Pat. No. 3,885,809 of Pitcher discloses an anti-roll suspension system in which a hydraulic strut for each wheel is controlled.
U.S. Pat. No. 3,871,681 of Piniot and assigned to Peugeot discloses a McPherson strut type assemblies supporting a pair of vehicle wheels, the assemblies being connected with a hydraulic pump for leveling or adjusting the trim of the vehicle.
U.S. Pat. No. 3,820,812 of Stubbs and assigned to Rover, discloses an active anti-roll suspension system including four hydraulic piston/cylinder assemblies acted upon by corresponding control units.
U.S. Pat. No. 3,752,497 of Enke et al. and assigned to Daimler-Benz, discloses another anti-roll suspension system including an actively controlled hydraulic piston/cylinder assembly for each wheel. A control valve is controlled during turns by a lateral acceleration pick-up.
U.S. Pat. No. 3,038,739 of Vogel discloses another anti-roll suspension system for a vehicle in which separate hydraulically controlled cylinders are connected between the supporting A-arms of an associated wheel.
U.S. Pat. No. 3,016,101 of Fiala and assigned to Daimler-Benz, discloses a system for improving the steering reaction of a vehicle. The system includes a hydropneumatic cylinder for each wheel, and the cylinders are operatively connected to a common control.
U.S. Pat. No. 2,976,052 of Hanna and assigned to Westinghouse, discloses another anti-roll system for a vehicle in which includes hydraulically controlled shock absorbers for each wheel.
Finally, U.S. Pat. No. 2,137,947 of Moore discloses another vehicle anti-roll system which includes a pair of double acting hydraulic shock absorbers that cooperate with a single transverse rear axle.